Since the father died the mother asked her husband's brother to help her pay the house mortgage, but after more than a year it seems that he doesn't want to pay anymore and getting paid having sex with the mother wasn't enough for him. So he made a new deal, he would pay the mortgage for more two years if her two daughters join the fun. They accepted it. The mortgage will be fully paid in 2 years and this was better then returning the house after being paying it for 18 years.